Applied Physics Express (APEX) is a letters journal devoted solely to rapid dissemination of up-to-date and concise reports on new findings in applied physics. It is published daily online and monthly for the printed version. The motto of APEX is high scientific quality and prompt publication. APEX is a sister journal of the Japanese Journal of Applied Physics (JJAP) and is published by IOP Publishing Ltd on behalf of the Japan Society of Applied Physics (JSAP).
This publication is partially supported by a Grant-in-Aid for Publication of Scientific Research Results from the Japan Society for the Promotion of Science.
From 2014, APEX will be published by IOP Publishing on behalf of The Japan Society of Applied Physics. All submissions and refereeing will continue to be handled by the APEX Editorial Office at The Japan Society of Applied Physics. To submit a paper to APEX, please connect to the editorial web site.
In the last 30 days
Shiro Kaneko et al 2014 Appl. Phys. Express 7 035102
Silicene or germanene is a monolayer honeycomb lattice made of Si or Ge, similar to graphene made of C. In this work, we have assessed the performance potentials of silicene nanoribbon (SiNR), germanene nanoribbon (GeNR), and graphene nanoribbon (GNR), which all have a sufficient band gap to switch off, as field-effect transistor (FET) channel materials. We have demonstrated that, by comparing at the same band gap of ∼0.5 eV, the GNR FET maintains an advantage over SiNR or GeNR FETs under an ideal transport situation, but SiNR and GeNR are attractive channel materials for high-performance FETs as well.
Yongzhen Wu et al 2014 Appl. Phys. Express 7 052301
A uniform and pinhole-free hole-blocking layer is necessary for high-performance perovskite-based thin-film solar cells. In this study, we investigated the effect of nanoscale pinholes in compact TiO 2 layers on the device performance. Surface morphology and film resistance studies show that TiO 2 compact layers fabricated using atomic layer deposition (ALD) contain a much lower density of nanoscale pinholes than layers obtained by spin coating and spray pyrolysis methods. The ALD-based TiO 2 layer acts as an efficient hole-blocking layer in perovskite solar cells; it offers a large shunt resistance and enables a high power conversion efficiency of 12.56%.
Takahiro Fukui et al 2014 Appl. Phys. Express 7 055201
Nitrogen-vacancy (NV) centers in diamond have attracted significant interest because of their excellent spin and optical characteristics for quantum information and metrology. To exploit these characteristics, precise control of the orientation of the NV axis in the lattice is essential. Here we show that the orientation of more than 99% of the NV centers can be aligned along the  axis by chemical vapor deposition homoepitaxial growth on (111) substrates. We also discuss the alignment mechanisms. Our result enables a fourfold improvement in the magnetic field sensitivity and opens new avenues to the optimum design of NV center devices.
Wataru Yashiro et al 2014 Appl. Phys. Express 7 032501
In X-ray grating interferometry, the fabrication of thick transmission gratings with pitches of several micrometers has been a key subject. We report on a metallic glass imprinting technique for fabricating an interferometer grating. We successfully fabricated an 8-µm-pitch, 10-µm-thick grating (26 mm 2) made of Pd 42.5Ni 7.5Cu 30P 20 metallic glass by using the technique, and as a demonstration we also performed X-ray phase imaging with the grating. The technique can be applied to fabricate not only X-ray but also neutron gratings potentially at high production rates and low costs and is expected to be widely used in the near future.
Cyril Pernot et al 2010 Appl. Phys. Express 3 061004
We report on the fabrication and characterization of AlGaN-based deep ultraviolet light-emitting diodes (LEDs) with the emission wavelength ranging from 255 to 280 nm depending on the Al composition of the active region. The LEDs were flip-chip bonded and achieved external quantum efficiencies of over 3% for all investigated wavelengths. Under cw operation, an output power of more than 1 mW at 10 mA was demonstrated. A moth-eye structure was fabricated on the back side of the sapphire substrate, and on-wafer output power measurement indicated a 1.5-fold improvement of light extraction.
Yuji Zhao et al 2011 Appl. Phys. Express 4 082104
We report a high-power blue light-emitting diode (LED) with a high external quantum efficiency and low droop on a free-standing (2021) GaN substrate. At a forward current of 20 mA, the LED showed a peak external quantum efficiency of 52% and an output power of 30.6 mW. In higher current density regions, the LED also showed outstanding performance, with droop ratios of 0.7% at 35 A/cm 2, 4.3% at 50 A/cm 2, 8.5% at 100 A/cm 2, and 14.3% at 200 A/cm 2. The output power and external quantum efficiency at 200 A/cm 2 were 266.5 mW and 45.3%, respectively.
Yasuhiro Yamada et al 2014 Appl. Phys. Express 7 032302
We studied the near-band-edge optical responses of solution-processed CH 3NH 3PbI 3 on mesoporous TiO 2 electrodes, which is utilized in mesoscopic heterojunction solar cells. Photoluminescence (PL) and PL excitation spectra peaks appear at 1.60 and 1.64 eV, respectively. The transient absorption spectrum shows a negative peak at 1.61 eV owing to photobleaching at the band-gap energy, indicating a direct band-gap semiconductor. On the basis of the temperature-dependent PL and diffuse reflectance spectra, we clarified that the absorption tail at room temperature is explained in terms of an Urbach tail and consistently determined the band-gap energy to be ∼1.61 eV at room temperature.
Yukio Nozaki et al 2015 Appl. Phys. Express 8 043001
Modulation of ferromagnetic resonance (FMR) linewidth owing to a spin transfer torque (STT) caused by the absorption of a pure spin current in a permalloy nanowire is demonstrated. To exclude the STT induced by the spin-polarized current, the pure spin current was produced using a lateral spin-valve structure. Self-homodyne FMR detection without applying an external sense current was used for minimizing the influence of Joule heating on the FMR linewidth. The linear variation of the FMR linewidth caused by the STT was clearly observed when the electrical current generating the pure spin current was below 1 mA.
Yun-Jing Li et al 2015 Appl. Phys. Express 8 042101
We report the study of an electrically driven nanopyramid-on-pillar green light-emitting diode (LED). The pyramid-on-pillar nanostructure was fabricated by top-down etching from a GaN template, followed by epitaxial regrowth. High-In-content InGaN/GaN multiple quantum wells (MQWs) were grown on semipolar pyramid and nonpolar pillar surfaces. The measured radiative lifetimes of MQWs on these two surfaces were 2 orders of magnitude shorter than that of a conventional c-plane (0001) MQW owing to their lower polarization field. Electrical injection performance was also demonstrated and discussed.
Makoto Miyoshi et al 2015 Appl. Phys. Express 8 021001
Nearly lattice-matched InAlN/Al x Ga 1− x N ( x = 0.1, 0.21, and 0.34) heterostructures with a 1-nm-thick AlN interfacial layer were grown on AlN/sapphire templates by metalorganic chemical vapor deposition. Capacitance–voltage and Hall effect measurements revealed that two-dimensional electron gases (2DEGs) with high densities exceeding 2 × 10 13/cm 2 were generated at the heterointerface for all samples. It was confirmed that the generation of high-density 2DEGs can be explained as being due to internal polarization effects. The sheet resistance increased from 1,267 to 1,919 Ω/sq with the increase in Al content in the AlGaN channel, owing to the decreases in 2DEG density and mobility.
This cloud represents the 50 most popular PACS codes from the latest 250 coded articles for this journal. The larger the code the more times it occurs in those 250 articles. Click on a code to link to the articles in that category.
42.55.Px 06.30.Bp 42.65.Ky 42.55.Rz 41.20.Jb 42.30.-d 42.55.Wd 42.55.Tv 42.15.Eq 07.57.Hm 42.60.Jf 06.30.Ft 24.60.Ky 42.60.Lh 42.65.Pc 42.30.Va 41.60.Cr 42.62.Cf 07.55.Db 41.75.Fr 42.25.Ja 42.25.Gy 07.50.Qx 32.80.Fb 07.07.Df 42.55.Xi 42.65.Jx 05.40.Ca 07.57.Pt 42.30.Lr 41.75.Jv 29.20.dg 07.60.-j 42.55.Sa 42.65.Es 03.67.-a 42.30.Wb 42.25.Bs 42.60.Da 33.50.Dq 07.60.Fs 29.25.Bx 07.85.Qe 07.55.Ge 42.25.Fx 42.40.Lx 42.50.Wk 42.55.Ye 42.50.Nn 07.57.-c